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Due to their complex architecture, the radiation sensitivity of general-purpose processors is intrinsically linked to the software that is executed. In order to obtain a consistent assessment of the fault tolerance during radiation experiments, it is necessary to have software representative of the final application. For this purpose, we are developing a methodology based on the application profiling tool that allows us to have a detailed view of the use of hardware resources according to the software profile. This analysis flow has been applied on a reduced instruction set computer (RISC-V) softcore for different applications allowing us to formulate a link between the fault tolerance and the software profile.

ABSTRACTThis work deals with the electromagnetic pulses (EMP) injection of transient faults into embedded cryptosystems. The purpose of this study is to deepen the understanding of the interaction of an electromagnetic (EM) field and a logic circuit (ASIC or FPGA). In this direction, a sign-off power analysis and a voltage (IR) drop analysis can be useful to localize possible circuit weaknesses and identify the most vulnerable regions to EMP attacks. The preliminary results of a sign-off power analysis conducted on a real circuit are provided and discussed. The long-term objective is the development of a model able to predict the effects of an EMP on a cryptosystem.

The mechanisms and kinetics of short pulse laser melting of single crystal and nanocrystalline Au films are investigated on the basis of the results of simulations performed with a model combining the molecular dynamics method with a continuum-level description of the laser excitation and subsequent relaxation of the conduction band electrons. A description of the thermophysical properties of Au that accounts for the contribution of the thermal excitation of d band electrons is incorporated into the model and is found to play a major role in defining the kinetics of the melting process. The effect of nanocrystalline structure on the melting process is investigated for a broad range of laser fluences. At high fluences, the grain boundary melting in nanocrystalline films results in a moderate decrease of the size of the crystalline grains at the initial stage of the laser heating and is followed by a rapid (within several picoseconds) collapse of the crystal structure in the remaining crystalline parts of the film as soon as the lattice temperature exceeds the limit of the crystal stability against the onset of rapid homogeneous melting (the limit of superheating). At low laser fluences, close to the threshold for the complete melting of the film, the initiation of melting at grain boundaries can steer the melting process along the path where the melting continues below the equilibrium melting temperature and the crystalline regions shrink and disappear under conditions of substantial undercooling. The unusual melting behavior of nanocrystalline films is explained on the basis of thermodynamic analysis of the stability of small crystalline clusters surrounded by undercooled liquid.

Dendritic cells (DC) acquire antigens through a number of cell surface structures including receptors for the Fc portion of immunoglobulins and mannose. Little is known about the effects of antigen uptake via these receptors on antigen processing and presentation. We compared the capacity of DC to generate CD4+and CD8+T cell responses after exposure to prostate-specific antigen (PSA) alone, PSA targeted to the mannose receptor (mannosylated PSA (PSA-m)), or PSA targeted to Fc receptors by combining PSA with an anti-PSA antibody (AR47.47). Autologous CD3+T cells were added to monocyte-derived immature DC that had been cultured with GM-CSF/IL-4 for 4 days, exposed to antigen, and matured with CD40L or TNFα/IFN-α. After several rounds of stimulation, T cell responses were assessed by intracellular IFN-γ production using flow cytometry. Both CD4+and CD8+T cell responses were observed after stimulation with DC exposed to the PSA/anti-PSA complexes, whereas CD4+predominated over CD8+T cell responses after stimulation with PSA-armed DC or PSA-m. These CD8+T cells responded when rechallenged with DC pulsed with HLA allele-restricted PSA peptides. These results indicate that PSA and PSA-m are processed primarily through pathways that favor HLA Class II presentation, while the PSA/anti-PSA immune complexes are processed through both Class I and Class II pathways in monocyte-derived DC. These findings have potential applications in designing more effective cancer vaccines for prostate cancer.

Two rounds of large-scale duplications are thought to have occurred in early vertebrate ancestry; this is now known as the “2R hypothesis.” They have led to the constitution of subfamilies of paralogous genes. Chromosomal regions that contain present-day paralogs (paralogous regions or paralogons) have been identified in mammals. We show that sets of paralogons (PGs) can be assembled in a tentative “human genome paralogy map” that includes all autosomes and X. A total of 14 PGs, containing more than 1600 genes, were assembled in this paralogy map. Genes that belong to the same PG are coparalogs. We show that identification of coparalogy can be used (i) to broaden data on gene mapping, (ii) to identify physical gene clusters that derive from early cis-duplications, and (iii) to speculate on coevolution and coregulation of genes sharing a common structure or function (functional clusters). Thus, coparalogy analyses should parallel phylogenetic analyses and can help draw hypotheses on gene and genome evolution.

Homeobox genes encode important developmental control proteins. In vertebrates, those encoding the proteins of the HOX class and their most closely related families, including paraHOX and metaHOX classes, are clustered in paralogous regions (or paralogons). We show that the majority of the other homeobox genes (we called contraHOX) can also be clustered and belong to paralogons in humans. This suggests that they duplicated during vertebrate evolution along the same processes as the HOXgenes. We tentatively assembled several paralogons in superparalogons. One of the superparalogons contains the contraHOXgenes. These observations were extended to hundreds of genes, and allowed to describe a primary human genome paralogy map.

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Immunohistochemical and biochemical analyses of hyperphosphorylated τ proteins, the major component of neurofibrillary tangles, were performed in different brain regions from patients presenting with postencephalitic parkinsonism. Neurofibrillary tangles were found in hippocampus, neocortical areas (mostly in supragranular layers), and several subcortical structures. By immunobloting, a τ protein triplet similar to the one seen in Alzheimer's disease was observed. This biochemical approach allows for the definition of postencephalitic parkinsonism from certain neurodegenerative disorders such as progressive supranuclear palsy and corticobasal degeneration.

The degeneration of nigral dopaminergic neurons in Parkinson disease is believed to be associated with oxidative stress. Since iron levels are increased in the substantia nigra of parkinsonian patients and this metal catalyzes the formation of free radicals, it may be involved in the mechanisms of nerve cell death. The cause of nigral iron increase is not understood. Iron acquisition by neurons may occur from iron-transferrin complexes with a direct interaction with specific membrane receptors, but recent results have shown a low density of transferrin receptors in the substantia nigra. To investigate whether neuronal death in Parkinson disease may be associated with changes in a pathway supplementary to that of transferrin, lactoferrin (lactotransferrin) receptor expression was studied in the mesencephalon. In this report we present evidence from immunohistochemical staining of postmortem human brain tissue that lactoferrin receptors are localized on neurons (perikarya, dendrites, axons), cerebral microvasculature, and, in some cases, glial cells. In parkinsonian patients, lactoferrin receptor immunoreactivity on neurons and microvessels was increased and more pronounced in those regions of the mesencephalon where the loss of dopaminergic neurons is severe. Moreover, in the substantia nigra, the intensity of immunoreactivity on neurons and microvessels was higher for patients with higher nigral dopaminergic loss. These data suggest that lactoferrin receptors on vulnerable neurons may increase intraneuronal iron levels and contribute to the degeneration of nigral dopaminergic neurons in Parkinson disease.

Heparan sulfate proteoglycans are believed to play an important role in amyloidosis as pathologic chaperones. They bind to amyloidogenic proteins and may mediate the deposition and fibrillogenesis of amyloid at specific tissue sites. In the present study, we demonstrate that heparan sulfate glycosaminoglycan and proteoglycan both bind to the amyloid peptide involved in Alzheimer's disease. The interaction of heparan sulfate proteoglycan and glycosaminoglycan can be inhibited by other sulfated compounds such as heparin, dextran sulfate and pentosan polysulfate. These polysaccharides which are currently used clinically, their derivatives or analogs may be effective as therapeutic agents to prevent or slow the progression of amyloidogenesis in Alzheimer's disease or other amyloidogenic disorders.